The article talks about NVidia racks, but also about their DSF [0], which is Ethernet-based (as opposed to Infiniband) built on switches using Cisco and Broadcom chipsets and custom ASIC xPU accelerators such as their own MTIA [1] which is built for them by Broadcom. So they are talking more than one approach simultaneously.

[0] https://engineering.fb.com/2024/10/15/data-infrastructure/op...

[1] https://ai.meta.com/blog/next-generation-meta-training-infer...